1. Field of the Invention
The present invention relates to a biological-information obtaining apparatus, particularly to a biological-information obtaining apparatus capable of obtaining information on oxygen saturation and a processing method thereof.
2. Description of the Related Art
The oxygen saturation represents the proportion of hemoglobin (Hb) that is oxyhemoglobin of blood. The hemoglobin of blood transports oxygen. The oxygen saturation is used as an index regarding a health condition of a living body, especially regarding a respiratory condition of the living body. As a medical device for determining oxygen saturation, for example, a pulse oximeter is known. A pulse oximeter is a device that noninvasively determines the oxyhemoglobin content of blood on the basis of the absorbance in a case in which a surface of a living body (for example, a finger tip) is irradiated with light of a certain wavelength and light of another wavelength.
For example, a pulse oximeter is known that obtains data on the absorbance of red light (a wavelength of 660 nm) and data on the absorbance of infrared light (a wavelength of 940 nm) by switching between light emission from a light-emitting diode that emits the red light and light emission from a diode that emits the infrared light, and calculates the oxygen saturation (see Japanese Unexamined Patent Application Publication No. 6-98881, FIG. 1).